KR20070116883A - Refrigerating apparatus - Google Patents

Abstract

A buffer chamber (71) is connected to the outlet port (33) of an expansion mechanism (60). The buffer chamber (71) is formed in the shape of a cylinder extending in the direction of the flow of a cooling medium, and has a cross-sectional area greater than that of the outlet port (33). A rectifying plate (75) having a mesh section (75a) of a circular shape is provided inside the buffer chamber (71). The variation of pressure is relieved by the supply of pressure and the absorption of pressure by the buffer chamber (71), and also drops of the cooling medium are fined when they are passed through the plate (75).

Description

Freezers {REFRIGERATING APPARATUS}

The present invention relates to a refrigerating device, and in particular, to countermeasures for reducing pressure pulsations.

Conventionally, a refrigeration apparatus of a vapor compression refrigeration cycle using carbon dioxide as a refrigerant is known. This type of refrigeration apparatus includes a refrigerant circuit in which a compressor, a cooler, an expander, and an evaporator are sequentially connected (see, for example, Patent Document 1).

In the refrigerant circuit of the said patent document 1, a refrigerant | coolant is compressed to a supercritical state by a compressor, and is cooled by a cooler. The cooled refrigerant expands in the expander to depressurize, and then repeats the circulation of evaporating in the evaporator to return to the compressor. This refrigerator is, for example, installed in a room with a cooler and is used as a heating device.

[Patent Document 1: Japanese Patent Application Laid-Open No. 2000-234814].

[Initiation of invention]

[Problem to Solve Invention]

Challenge

However, in the above-mentioned conventional refrigeration apparatus, there is a problem that particularly large vibration occurs at the outlet side of the expander. Specifically, when a volume type is used as the expander, the suction flow rate during the suction process and the discharge flow rate during the discharge process are not constant, so that pressure pulsations occur at the inlet and outlet sides of the expander, and vibrations are caused by the pressure pulsations. Occurs. In addition, since the refrigerant in the gas-liquid two-phase state flows out of the expander, there is a problem that a larger vibration occurs at the outlet side of the expander when droplets of the refrigerant collide with a pipe or the like. Therefore, there is a high possibility of causing damage to the equipment due to vibration on the outlet side of the inflator, and there is a fear that the reliability will be remarkably impaired.

This invention is made | formed in view of such a point, Comprising: It aims at reducing a pressure pulsation at least on the exit side of an expander, and aiming at reducing a vibration.

[Means for solving the problem]

The solving means devised by this invention is as showing below.

The first solution is based on the refrigeration apparatus provided with the refrigerant | coolant circuit 20 which the volume expander 60 is pipe-connected and performs a vapor compression refrigeration cycle. The refrigerant circuit 20 has a larger flow passage cross-sectional area of the refrigerant in the outlet pipe of the volume expander 60 than the outlet pipe, and changes the pressure fluctuation of the refrigerant flowing out of the volume expander 60. The flow path expansion part 71 which relaxes is provided.

In the above solution means, the flow passage enlargement portion 71 constitutes a pressure buffer space for mitigating the outflow refrigerant pressure fluctuation of the volume expander 60. Therefore, the pressure fluctuations (pressure pulsations) generated at the outlet side of the volume expander 60 are alleviated by the flow channel enlargement portion 71. As a result, vibration of the entire apparatus due to pressure fluctuations is suppressed.

The second solution is based on the refrigeration apparatus provided with the refrigerant | coolant circuit 20 which the volume expander 60 is pipe-connected and performs a vapor compression refrigeration cycle. The refrigerant circuit 20 has a larger flow passage cross-sectional area of the refrigerant in the middle of the outlet pipe of the volume expander 60 than the outlet pipe, and extends along the flow direction of the refrigerant. 71).

In the above solution means, for example, as shown in FIG. 3, the flow passage enlargement portion 71 is formed into a tubular container extending in the flow direction of the refrigerant, and the inside of the container constitutes a pressure buffer space. Specifically, in the case where the flow rate of the refrigerant from the volume expander 60 is increased and the pressure is increased, the amount of the refrigerant is stored in the flow path expansion portion 71 to absorb the pressure. On the contrary, when the amount of refrigerant flowed out from the volume expander 60 is reduced and the pressure is reduced, the amount of the refrigerant flowed out of the flow path expansion portion 71 from the flow path expansion portion 71 to the outlet pipe and the pressure is supplied. That is, the flow path expansion part 71 moderates the pressure fluctuation by adjusting the refrigerant flow rate on the outlet side in response to the pressure fluctuation at the outlet side of the volume expander 60. As a result, pressure fluctuations at the outlet side of the volume expander 60 are suppressed, and vibration of the entire apparatus is suppressed.

The third solution means, in the second solution means, the flow path expansion portion 71 is arranged in a state extending in the vertical direction, so that the refrigerant flowed from the upper flows vertically downward and flows out from the lower surface, the volumetric expander ( 60) to the outlet side pipe.

In the above solution means, as shown in Fig. 10, the flow path enlargement portion 71 is formed into a tubular container extending in the vertical direction, that is, in the vertical direction. The refrigerant flowing out of the volume expander 60 flows in from the upper portion of the flow path expansion portion 71 and flows vertically downward, and flows out from the lower surface to the outlet pipe, thereby preventing the liquid refrigerant from being stored on the lower surface. have. That is, the coolant flowing out of the volume expander 60 is in the gas-liquid two-phase state, but the liquid coolant reliably flows out of the flow path expansion part 71.

In the fourth solving means, in the first or second solving means, the rectifying means (75, 76) of the refrigerant is disposed inside the flow passage enlargement (71).

In the above solving means, the flow of the refrigerant flowing into the flow path enlargement section 71 is stabilized by the rectifying means 75 and 76. That is, since the flow of the liquid refrigerant among the refrigerant flowing into the flow path expansion part 71 is stabilized, it is possible to prevent the liquid refrigerant from severely colliding with the inner wall of the pipe or the like. Therefore, the rectification means 75, 76 suppresses the vibration generated by the liquid refrigerant colliding with the tube wall or the like. As a result, the vibration of the whole apparatus is further suppressed with the suppression effect of a pressure pulsation.

The fifth solution means, in the fourth solution, the rectifying means 76 is a rectifying plate formed in a plate shape having a plurality of through-holes, arranged in the flow direction of the refrigerant.

In the above solution, as shown in FIG. 6, the refrigerant flowing into the flow path enlargement portion 71 flows through the plurality of through holes of the rectifying plate, so that the flow of the refrigerant is stabilized. In addition, when the refrigerant passes through the through hole, the flow velocity of the refrigerant is increased, and the liquid refrigerant is refined by the force of the flow velocity. Thereby, even if a liquid refrigerant collides with a pipe wall etc., the impact is small. Therefore, vibration of the apparatus is further suppressed.

The sixth solution means, in the fourth solution means, the rectifying means 75 is a rectifying plate formed of a plate-like mesh member, which is disposed opposite to the flow direction of the refrigerant.

In the above solution, as shown in FIG. 3, the refrigerant flowing into the flow path enlargement portion 71 flows through the mesh portion of the rectifying plate, so that the flow of the refrigerant is stabilized. Also, when the refrigerant passes through the mesh portion, the liquid refrigerant contained in the refrigerant is refined by the mesh portion. Thereby, even if liquid refrigerant collides with a pipe wall etc., the impact is small. Therefore, vibration of the apparatus is further suppressed.

In the seventh solution means, in the second or third solution means, a partition plate 77 having a through hole and partitioning the inside in the flow direction of the coolant is disposed in the flow path expansion part 71.

In the above-mentioned solution means, for example, as shown in FIG. 7, the interior of the flow path enlarged portion 71 is partitioned into an upstream space and a downstream space by the partition plate 77. That is, the flow path enlargement section 71 includes two pressure buffer spaces, for example. A through hole is formed in this partition plate 77, and the upstream space and the downstream space communicate with each other by this through hole. Therefore, in this flow path expansion section 71, the refrigerant pressure fluctuation at the outlet side of the expansion mechanism 60 is alleviated in two stages. In addition, when two or more partition plates 77 are used to form three or more pressure buffer spaces, the pressure fluctuations are alleviated in multiple stages. As a result, the shock due to the sudden pressure change is suppressed. Therefore, vibration of the whole apparatus is further suppressed.

In an eighth solution, the refrigerant is carbon dioxide in the first or second solution.

In the above solution, since carbon dioxide is used as the refrigerant circulating in the refrigerant circuit 20, it is possible to provide a device and a device that are environmentally friendly. Particularly, in the case of carbon dioxide, since it is compressed to a critical pressure state, the pressure fluctuation at the outlet side of the volume expander 60 becomes large, but this pressure fluctuation is reliably and effectively suppressed.

[Effects of the Invention]

Therefore, according to the first solution, during the outlet side piping of the volumetric expander 60, a larger flow passage cross-sectional area of the refrigerant is formed than the outlet side piping, and the pressure fluctuation of the refrigerant flowing out of the volumetric expander 60 is prevented. Since the passage enlargement part 71 which relaxes is arrange | positioned, the vibration of the apparatus resulting from a pressure fluctuation can be suppressed. As a result, damage to the equipment can be prevented.

Further, according to the second solution, the flow passage enlarged portion formed in a tubular shape which has a larger flow passage cross-sectional area of the refrigerant than the outlet pipe in the middle of the outlet-side piping of the volume expander 60 and continues along the flow direction of the refrigerant. Since 71 is arrange | positioned, the pressure supply and pressure absorption can be reliably supplied from the flow path expansion part 71 to the exit piping. As a result, since the pressure fluctuation can be suppressed, the vibration of the entire apparatus can be suppressed.

Further, according to the third solution, since the coolant flows vertically in the flow path enlargement portion 71 and flows out from the lower surface, it is possible to prevent the liquid refrigerant from accumulating in the flow path expansion portion 71.

In addition, according to the fourth to sixth solutions, the rectifying means 75, 76 for the coolant is arranged in the channel enlargement portion 71, so that the flow of the coolant can be reliably stabilized. Thereby, the collision with the piping wall of a liquid refrigerant can be suppressed. Therefore, it is possible to suppress vibration caused by the collision of the liquid refrigerant.

In addition, according to the seventh solution, since the partition plate 77 is disposed in the flow path expansion part 71 and a plurality of pressure buffer spaces are formed therein, the pressure fluctuation can be reduced in multiple stages. Therefore, the shock caused by the sudden pressure fluctuation can be alleviated. Thereby, the vibration of the whole apparatus can be suppressed further, and the damage of apparatus can be prevented further.

In addition, according to the eighth solution, since carbon dioxide is used as the refrigerant circulating in the refrigerant circuit 20, it is possible to provide an environment-friendly device and apparatus. Particularly, in the case of carbon dioxide, since the pressure is compressed to a critical pressure state, the pressure fluctuation becomes large, but this pressure fluctuation can be reliably and effectively suppressed.

1 is a piping system diagram showing an air conditioner according to the embodiment.

FIG. 2: shows the principal part of the expansion mechanism which concerns on embodiment, (A) is a cross-sectional view, (B) is a longitudinal cross-sectional view.

3 shows a buffer container according to the first embodiment, wherein (A) is a longitudinal cross-sectional view and (B) is a cross-sectional view.

4 is a cross sectional view showing an operating state of the expansion mechanism according to the embodiment;

5 is a characteristic diagram showing the flow rate and pressure of the expansion mechanism discharge refrigerant, and (B) is a characteristic diagram showing the magnitude of vibration occurring at the outlet side of the expansion mechanism.

FIG. 6: shows the buffer container which concerns on the modification of 1st Embodiment, (A) is a longitudinal cross-sectional view, (B) is a cross-sectional view.

FIG. 7: shows the buffer container which concerns on 2nd Embodiment, (A) is a longitudinal cross-sectional view, (B) is a cross-sectional view.

8 is a longitudinal sectional view showing a buffer container according to a modification of the second embodiment.

9 is a longitudinal sectional view showing the buffer container according to the third embodiment.

10 is a longitudinal sectional view showing a buffer container according to a modification of the third embodiment.

Fig. 11 is a characteristic diagram showing the flow rate and pressure of a conventional refrigerant for discharging the expansion mechanism, and (B) is a characteristic diagram showing the magnitude of vibration occurring at the outlet side of the conventional expansion mechanism.

[Description of the code]

10: air conditioner (refrigeration device) 20: refrigerant circuit

60: expansion mechanism (volume expander) 71: buffer container (Euro expansion part)

75, 76: rectification plate (rectification means) 77: partition plate

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail based on drawing.

[First embodiment]

As shown in FIG. 1, the air conditioner 10 of this 1st Embodiment comprises the refrigeration apparatus which concerns on this invention. The air conditioner 10 includes an outdoor heat exchanger 23, an indoor heat exchanger 24, two crossover switching valves 21 and 22, and a compression expansion unit 30 connected to each other in a refrigerant circuit formed in a closed circuit ( 20). The refrigerant circuit 20 is filled with carbon dioxide (CO ₂ ) as a refrigerant, and the refrigerant is circulated to execute a vapor compression refrigeration cycle.

The outdoor heat exchanger 23 constitutes a heat source side heat exchanger, and the indoor heat exchanger 24 constitutes a utilization side heat exchanger. The outdoor heat exchanger 23 and the indoor heat exchanger 24 are both cross fin finned tube heat exchangers. The outdoor heat exchanger 23 is configured such that the refrigerant circulating in the refrigerant circuit 20 exchanges heat with outdoor air. The indoor heat exchanger 24 is configured such that the refrigerant circulating in the refrigerant circuit 20 exchanges heat with indoor air.

In the compression expansion unit (30), the compression mechanism (50), the electric motor (40), and the expansion mechanism (60) are housed in a casing. The compression mechanism 50, the electric motor 40, and the expansion mechanism 60 are connected in this order by a shaft 45 which is a rotation shaft. The compression mechanism 50 constitutes a rotary compressor of the swinging piston type. The expansion mechanism 60 is a swinging piston-type rotary expander and constitutes a volume expander 60 according to the present invention.

The compression expansion unit 30 includes a suction port 34 through which the refrigerant of the refrigerant circuit 20 is sucked into the compression mechanism 50, and the refrigerant compressed by the compression mechanism 50 is discharged into the refrigerant circuit 20. The discharge port 31 is provided. The compression expansion unit 30 further includes an inlet port 32 through which the refrigerant of the refrigerant circuit 20 is introduced into the expansion mechanism 60, and a refrigerant expanded by the expansion mechanism 60 to the refrigerant circuit 20. An outlet port 33 for introducing is installed. In addition, the detail of the said expansion mechanism 60 is mentioned later.

The first four-way valve 21 is provided with four ports. The first four-way switching valve 21 has a third port at a gas port end where the first port is at the discharge port 31 of the compression expansion unit 30 and the second port is at one end of the indoor heat exchanger 24. The fourth port is connected to the suction port 34 of the compression expansion unit 30 at the gas side end which is one end of the outdoor heat exchanger 23. The first four-way valve 21 has a state in which a first port and a second port communicate with each other, and a third port and a fourth port communicate with each other (a state indicated by a solid line in FIG. 1), and the first port and the third port. The port is in communication with the second port and the fourth port is configured to be switched to the state (indicated by the dotted line in Fig. 1) in communication.

The second four-way switching valve 22 has four ports. The second four-way switching valve 22 has a first port at the outlet port 33 of the compression expansion unit 30, a second port at the liquid side end at the other end of the outdoor heat exchanger 23, and a third port. At the other end of the indoor heat exchanger 24, the fourth port is connected to the inlet port 32 of the compression expansion unit 30, respectively. The second four-way valve 22 has a state in which the first port and the second port communicate with each other, and a third port and the fourth port communicate with each other (the state indicated by a solid line in FIG. 1), and the first port and the third port. The port is in communication with the second port and the fourth port is configured to be switched to the state (indicated by the dotted line in Fig. 1) in communication.

The expansion mechanism 60 will be described with reference to FIG. 2. 2 (A) shows a cross section perpendicular to the central axis of the shaft 45, and FIG. 2 (B) shows a longitudinal section along the center axis of the shaft 45. As shown in FIG.

The expansion mechanism (60) includes a front head (61), a rear head (62), a cylinder (63), and a rotating piston (67).

The cylinder 63 has one end face blocked by the front head 61 and the other end face blocked by the rear head 62.

The rotating piston 67 is formed in an annular or cylindrical shape, and is accommodated in the cylinder 63. In addition, the rotary piston 67 is in sliding contact with the inner circumferential surface of the cylinder 63 and both end surfaces are in sliding contact with the front head 61 and the rear head 62. In the cylinder 63, an expansion chamber 65 is formed between the inner circumferential surface and the outer circumferential surface of the rotary piston 67.

The shaft 45 penetrates the rotary piston 67. The shaft 45 has a main shaft portion 46, and an eccentric portion 47 having a diameter larger than the outer diameter of the main shaft portion 46 is formed at one end of the main shaft portion 46. This eccentric part 47 is eccentrically by a predetermined amount from the axial center of the main shaft part 46. Then, the eccentric part 47 is freely fitted into the rotary piston 67 in rotational motion.

Moreover, the blade 68 formed in plate shape is integrally formed in the said rotary piston 67. As shown in FIG. The blade 68 protrudes outward from the outer circumferential surface of the rotary piston 67 and is configured to partition the expansion chamber 65 in the cylinder 63 into the high pressure side (suction / expansion side) and the low pressure side (discharge side). do.

The cylinder 63 is equipped with a pair of bushes 69. The pair of bushes 69 hold the blades 68 therebetween and support the blades 68 freely in rotational motion and freely moving forward and backward.

The inflow port 32 penetrates the rear head 62 and is open in a range in which the end thereof is in sliding contact with the eccentric portion 47 of the inner surface of the rear head 62. That is, the inflow port 32 is opened at a position where the end thereof does not directly communicate with the expansion chamber 65. On the other hand, the outflow port 33 penetrates through the cylinder 63 in the radial direction and is opened on the low pressure side of the expansion chamber 65. The inflow port 32 and the outflow port 33 extend out of the casing of the compression expansion unit 30 by piping.

The rear head 62 is formed with a recessed groove passage 9a. As shown in Fig. 2A, one end of the passage 9a is located slightly inward from the inner circumferential surface of the cylinder 63, while the other end includes the rear head 62 and the eccentric portion 47. It is located in the sliding contact part. The passage 9a is configured to communicate with the expansion chamber 65.

In the eccentric portion 47 of the shaft 45, a concave groove-shaped connecting passage 9b is formed. As shown in Fig. 2A, the connecting passage 9b is formed in an arc shape extending along the outer circumference of the eccentric portion 47. The connecting passage 9b is configured to intermittently communicate the inflow port 32 and the passage 9a by moving in accordance with the rotation of the shaft 45.

In the refrigerant circuit 20, as a feature of the present invention, a pressure buffer means 70 for suppressing the pressure fluctuation (pressure pulsation) of the outlet side of the expansion mechanism 60 is provided. This pressure buffer means 70 is provided with a buffer container 71. The buffer container 71 is connected in the middle of the outlet pipe of the expansion mechanism 60.

As shown in Figure 3, the buffer container 71 is formed in a substantially cylindrical container. This buffer container 71 has a body portion 72, an inlet end 73 and an outlet end 74. The body portion 72 is formed in a cylindrical shape in cross section. The inlet end 73 and the outlet end 74 are formed continuously at both ends of the body portion 72 and block both ends. In addition, the volume of the buffer container 71 is larger than the volume of the expansion chamber 65 of the expansion mechanism 60, and preferably 10 times or more of the volume of the expansion chamber 65.

The outlet port 33 of the expansion mechanism 60 is connected to the center of the inlet end 73, and to the center of the outlet end 74 is a part of the refrigerant pipe and is the first of the second four-way switching valve 22. The connecting pipe P leading to the port is connected. This connecting pipe P, together with the outlet port 33, constitutes an outlet side pipe of the expansion mechanism 60. The buffer container 71 is coaxially connected to the outlet port 33 and the connection pipe P, and the refrigerant flowing from the outlet port 33 flows horizontally and flows out into the connection pipe P. That is, the buffer container 71 is formed in a tubular shape extending along the flow direction of the refrigerant. As described above, since the buffer container 71 is formed in a cylindrical shape, the flow resistance of the refrigerant is smaller than that in the case where the buffer container 71 is formed in, for example, a cross section.

The cross-sectional area of the body portion 72 is formed to be much larger than the cross-sectional area of the outlet port 33 and the connection pipe (P). The buffer container 71 absorbs and stores the refrigerant in the outlet port 33 when the refrigerant pressure in the outlet port 33 increases, and conversely, when the refrigerant pressure in the outlet port 33 decreases, the refrigerant flows into the outlet port. And to discharge at 33. That is, the buffer container 71 constitutes an enlarged flow path of the outlet side pipe of the expansion mechanism 60, and the inside thereof constitutes a pressure buffer space.

The rectifying plate 75 is disposed inside the buffer container 71. The rectifying plate 75 constitutes refrigerant rectifying means for stabilizing the flow of the refrigerant.

The rectifying plate 75 is formed in a disk shape in its entirety. The rectifying plate 75 is formed so that its outer diameter is almost equal to the inner diameter of the body portion 72 of the buffer container 71, and the outer portion is provided in contact with the entire inner portion of the body portion 72. That is, this rectifying plate 75 is located so as to face in the flow direction of the refrigerant. As shown in FIG. 3B, the rectifying plate 75 has a mesh portion 75a having the entire inner circumference in a net shape. The rectifying plate 75 is configured so that the refrigerant in the droplet state becomes fine when the refrigerant passes through the mesh portion 75a. The refrigerant introduced into the buffer container 71 flows downward through the mesh portion 75a of the rectifying plate 75. Here, the rectifying plate 75 is disposed toward the inlet end 73 inside the buffer container 71. FIG. 3B shows a cross section taken along the line X-X in FIG. 3A.

Operation operation

Next, the operation of the air conditioner 10 will be described. Here, the operation during the cooling operation and the heating operation of the air conditioner 10 will be described, and then the operation of the expansion mechanism 60 will be described.

<Cooling operation>

During this cooling operation, the motor 45 of the compression expansion unit 30 is turned on in a state where the first four-way switching valve 21 and the second four-way switching valve 22 are switched to the state shown by the dotted lines in FIG. 1. When energized, the refrigerant circulates in the refrigerant circuit 20 to perform a vapor compression freezing cycle.

The high pressure refrigerant compressed by the compression mechanism (50) is discharged from the compression expansion unit (30) through the discharge port (31). In this state, the pressure of the high pressure refrigerant is higher than its critical pressure. This high pressure refrigerant is sent to the outdoor heat exchanger (23) via the first four-way switching valve (21). In this outdoor heat exchanger (23), the introduced high pressure refrigerant radiates heat to outdoor air.

The high pressure refrigerant radiated by the outdoor heat exchanger 23 flows into the expansion chamber 65 of the expansion mechanism 60 from the inlet port 32 through the second cross switching valve 22. In this expansion chamber 65, the high pressure refrigerant expands, and its internal energy is converted into rotational power of the shaft 45. The low pressure refrigerant after expansion flows out from the compression expansion unit 30 through the outlet port 33 and is sent to the indoor heat exchanger 24 through the second four-way switching valve 22.

In the indoor heat exchanger (24), the introduced low pressure refrigerant absorbs and evaporates from the indoor air, and the indoor air is cooled. The low pressure gas refrigerant from the indoor heat exchanger 24 is sucked into the compression mechanism 50 of the compression expansion unit 30 from the suction port 34 through the first four-way switching valve 21. The compression mechanism 50 then compresses and discharges the sucked refrigerant again.

〈Heating driving〉

In this heating operation, when the first cross switching valve 21 and the second cross switching valve 22 are switched to the state shown by the solid line in FIG. 1, the electric motor 45 of the compression expansion unit 30 is energized. The refrigerant circulates in the refrigerant circuit 20, and a vapor compression freezing cycle is performed.

The high pressure refrigerant compressed by the compression mechanism (50) is discharged from the compression expansion unit (30) through the discharge port (31). In this state, the pressure of the high pressure refrigerant is higher than its critical pressure. This high pressure refrigerant is sent to the indoor heat exchanger (24) via the first four-way switching valve (21). In this indoor heat exchanger (24), the introduced high-pressure refrigerant radiates heat to the indoor air, and the indoor air is heated.

The high pressure refrigerant radiated by the indoor heat exchanger 24 flows into the expansion chamber 65 of the expansion mechanism 60 from the inlet port 32 through the second cross switching valve 22. In this expansion chamber 65, the high pressure refrigerant expands, and its internal energy is converted into rotational power of the shaft 45. After expansion, the low pressure refrigerant flows out of the compression expansion unit 30 through the outlet port 33 and is sent to the outdoor heat exchanger 24 through the second four-way switching valve 22.

In the outdoor heat exchanger (23), the introduced low pressure refrigerant absorbs heat from the outdoor air and evaporates. The low pressure gas refrigerant from the outdoor heat exchanger 23 is sucked from the suction port 34 to the compression mechanism 50 of the compression expansion unit 30 through the first crossover valve 21. The compression mechanism 50 then compresses and discharges the sucked refrigerant again.

<Operation of expansion mechanism>

The operation of the expansion mechanism 60 will be described with reference to FIG. 4. When the high-pressure refrigerant in the supercritical state flows into the expansion chamber 65 of the expansion mechanism 60, the shaft 45 rotates counterclockwise in FIG. 4 shows the rotation angle of the shaft 45 by 45 degrees.

When the rotational angle of the shaft 45 is 0 °, the end of the inflow port 32 is blocked by the end surface of the eccentric portion 47. At this point, the expansion chamber 65 is blocked from the inlet port 32, and the high pressure refrigerant does not flow into the expansion chamber 65.

When the rotation angle of the shaft 45 is 45 °, the inflow port 32 is in a state of communicating with the connecting passage 9b. The connecting passage 9b also communicates with the grooved passage 9a. This groove-like passage 9a is in a state where the upper end portion in FIG. 4 is out of the end surface of the rotary piston 67 and communicates with the high pressure side of the expansion chamber 65. At this point, the expansion chamber 65 is brought into communication with the inflow port 32 via the grooved passage 9a and the connection passage 9b, and the high pressure refrigerant flows into the high pressure side of the expansion chamber 65. That is, the inlet of the high pressure refrigerant into the expansion chamber 65 is started while the rotation angle of the shaft 45 reaches from 0 ° to 45 °.

When the rotational angle of the shaft 45 is 90 °, the expansion chamber 65 is still in communication with the inflow port 32 via the passage 9a and the connecting passage 9b. Therefore, the high pressure refrigerant continues to flow to the high pressure side of the expansion chamber 65 until the rotation angle of the shaft 45 reaches from 45 ° to 90 °.

When the rotational angle of the shaft 45 is 135 °, the connecting passage 9b is in a state deviated from both the grooved passage 9a and the inflow port 32. At this point, the expansion chamber 65 is blocked from the inlet port 32, and the high pressure refrigerant does not flow into the expansion chamber 65. That is, the inlet of the high pressure refrigerant into the expansion chamber 65 is finished while the rotation angle of the shaft 45 reaches from 90 ° to 135 °.

When the inflow of the high pressure refrigerant into the expansion chamber 65 is finished, the high pressure side of the expansion chamber 65 becomes a closed space, and the refrigerant therein expands. That is, as shown in each figure of FIG. 4, the shaft 45 rotates and the high pressure side volume of the expansion chamber 65 increases. In the meantime, the low pressure refrigerant after expansion continues to be discharged through the outflow port 33 from the low pressure side of the expansion chamber 65 communicated with the outflow port 33.

Refrigerant expansion in the expansion chamber (65) occurs when the contact between the rotary piston (67) and the cylinder (63) reaches the outlet port (33) while the rotation angle of the shaft (45) reaches from 360 ° to 360 °. Continue until. When the contact portion between the rotary piston 67 and the cylinder 63 crosses the outlet port 33, the expansion chamber 65 communicates with the outlet port 33, and the expanded refrigerant begins to be discharged. After that, when the contact portion between the rotary piston 67 and the cylinder 63 passes through the outlet port 33, the expansion chamber 65 is blocked from the outlet port 33, and the discharge of the expanded refrigerant is completed.

As described above, the suction and discharge of the refrigerant in the volume expansion mechanism 60 is determined according to the rotation angle of the shaft 45. As a result, the suction flow rate and the discharge flow rate of the refrigerant in the expansion mechanism 60 are intermittent through the cycle. Therefore, pressure fluctuations (pressure pulsations) of the suction refrigerant and the discharge refrigerant occur in the inlet port 32 and the outlet port 33 of the expansion mechanism 60. This pressure fluctuation causes vibration of the whole device. In the outflow port 33 of the expansion mechanism 60, since the refrigerant after expansion is in the gas-liquid two-phase state, vibration occurs even when the refrigerant in the droplet state collides with the inner wall of the pipe. In this way, a vibration greater than the inlet side occurs on the outlet side of the expansion mechanism 60.

Next, the operation of the pressure buffer means 70 will be described. When the pressure fluctuation of the discharged refrigerant occurs, the pressure supply and pressure absorption are performed by the buffer container 71.

For example, when the discharge refrigerant flow rate of the outlet port 33 decreases and the refrigerant pressure decreases, a larger amount of refrigerant flows from the buffer container 71 into the connection pipe P than usual. Thereby, the pressure fall of the refrigerant | coolant in connection pipe | tube P is suppressed. In addition, when the discharge refrigerant flow rate in the outflow port 33 is increased to increase the refrigerant pressure, the increased amount of the refrigerant flowing into the buffer container 71 is stored in the buffer container 71 as it is. The remaining refrigerant flows out into the connection pipe (P). As a result, the refrigerant pressure increase in the connecting pipe P is suppressed. That is, the buffer container 71 is configured to discharge and absorb the refrigerant according to the pressure fluctuation in the outflow port 33 and to keep the flow rate of the refrigerant in the connection pipe P always constant.

In addition, the refrigerant flowing into the buffer container 71 from the outlet port 33 passes through the mesh portion 75a of the rectifying plate 75 to stabilize the flow. As a result, droplets of refrigerant do not collide with the pipe wall as severely as in the prior art. Further, when the refrigerant passes through the mesh portion 75a, the droplet refrigerant cools, so that the impact is reduced even when the droplet refrigerant collides with the pipe wall.

As described above, as shown in FIG. 5A, the pressure fluctuation of the refrigerant in the outlet pipe of the expansion mechanism 60 is a conventional case in which the buffer container 71 is not provided (FIG. 11A). It can be seen that it is significantly smaller. In addition, as shown in FIG. 5B, the vibration in the outlet pipe of the expansion mechanism 60 is smaller than the conventional case (see FIG. Able to know.

Effect of the first embodiment

As described above, according to the first embodiment, the buffer container 71 is formed to be larger than the flow passage cross-sectional area of the outlet port 33 of the expansion mechanism 60 to mitigate fluctuations in the discharge refrigerant pressure of the expansion mechanism 60. ) Is provided in the middle of the outlet pipe of the expansion mechanism 60, so that the discharge refrigerant pressure fluctuation of the expansion mechanism 60 can be reliably suppressed, and the vibration of the entire apparatus due to the pressure fluctuation can be suppressed. .

In addition, since the rectifying plate 75 having a mesh shape is disposed in the buffer container 71, the flow of the refrigerant flowing into the buffer container 71 can be stabilized, and the refrigerant in the droplet state included in the refrigerant can be stabilized. Can be refined. As a result, it is possible to prevent the refrigerant in the droplet state from severely colliding with the pipe wall or the like, and the impact can be alleviated since the droplets are small even if they collide with each other. Therefore, the vibration generated by the liquid refrigerant colliding with the pipe wall or the like can be suppressed, so that the vibration of the entire apparatus can be further suppressed in addition to the above-described effects. As a result, there is no fear that the equipment is damaged.

In addition, since the discharge refrigerant pressure fluctuation in the expansion mechanism 60 is suppressed, the discharge pressure loss can be suppressed, and the efficiency decrease of the volumetric expansion mechanism 60 can be prevented, and also caused by the rapid pressure fluctuation. Noise can be prevented.

In addition, since the buffer container 71 is formed to have a tubular shape running along the flow of the coolant, the flow resistance of the coolant can be reduced, for example, as compared with the case in which the shape of the buffer container 71 is perpendicular to the flow of the coolant. Can be. Therefore, the fall of the driving efficiency by providing the flow path expansion part 71 can be suppressed.

In addition, since carbon dioxide is used as the refrigerant of the refrigerant circuit 20, it is possible to provide an environment-friendly device. Particularly, in the case of carbon dioxide, the pressure fluctuation increases by the compression to the critical pressure state, but the pressure pulsation can be reliably reduced.

Modified Example of First Embodiment

The modification of the said 1st Embodiment is demonstrated, referring FIG. In this modification, the configuration of the buffer container 71 rectifying plate 75 according to the first embodiment is changed. That is, instead of forming the rectifying plate 75 in a mesh form, the first embodiment is configured to form a small hole 76a that is a through hole over the entire surface of the rectifying plate 76 (FIG. 6). (B)). And (B) of FIG. 6 shows the cross section in the X-X ray of FIG. 6 (A).

In this case, the refrigerant flowing into the buffer container 71 flows through the small hole 76a of the rectifying plate 76, whereby the refrigerant flow is stabilized. In addition, when the refrigerant passes through the small hole 76a, the flow velocity thereof is accelerated, and the force in the droplet state is refined by the force. Therefore, similarly to the first embodiment, the vibration generated by the refrigerant in the droplet state colliding with the pipe wall or the like can be suppressed. Other configurations, operations and effects are the same as in the first embodiment.

Second Embodiment

Next, a second embodiment of the present invention will be described with reference to FIG.

In the second embodiment, the first embodiment is configured such that the partition plate 77 is disposed in the buffer container 71 instead of the rectifying plate 75 in the buffer container 71. Specifically, the partition plate 77 is formed in a disk shape, the outer diameter is formed almost equal to the inner diameter of the body portion 72 of the buffer container 71. In the center of the partition plate 77, one circular through hole 77a is formed as a circulation hole for the refrigerant. The inner diameter of the through hole 77a is formed to have a diameter substantially equal to the inner diameter of the outlet port 33. The partition plate 77 is disposed at the inner center of the buffer container 71, and the partition plate 77 is partitioned into an upstream space on the outlet port 33 side and a downstream space on the connection pipe P side. That is, the inside of the buffer container 71 is composed of two pressure buffer space.

In this case, for example, when the discharge refrigerant pressure of the expansion mechanism 60 decreases, the refrigerant flows from the upstream space to the downstream space, and flows out into the connection pipe P together with the refrigerant in the downstream space. On the contrary, when the discharge refrigerant pressure of the expansion mechanism 60 rises, the refrigerant corresponding to the amount increased from the outlet port 33 flows into the upstream space, and part of the flow flows into the downstream space. That is, in the buffer container 71, the pressure fluctuation of the discharged refrigerant is relaxed in two stages. As a result, the shock caused by the sudden pressure fluctuation can be alleviated. Therefore, vibration of the whole apparatus can be suppressed. Other configurations, operations and effects are the same as in the first embodiment.

The number of partition plates 77 is not limited to this, and may be arranged so as to form a plurality of pressure buffer spaces. For example, as shown in FIG. 8, three partition plates 77 may be arranged to form four pressure buffer spaces. In this case, the discharge refrigerant pressure fluctuation of the expansion mechanism 60 is alleviated in four stages. Therefore, the generation of vibration can be further suppressed.

[Third Embodiment]

Next, a third embodiment of the present invention will be described with reference to FIG.

In the third embodiment, the rectifying plate 75 of the first embodiment and the partition plate 77 of the second embodiment are arranged one by one in the buffer container 71. Specifically, the partition plate 77 and the rectifying plate 76 are arranged in this order from the outlet port 33 side. That is, in the buffer container 71, the inside is divided into two pressure buffer spaces, and the rectifying plate 75 is disposed in the pressure buffer space downstream thereof. Therefore, the vibration due to the pressure fluctuation, the vibration due to the collision of the refrigerant in the droplet state with the pipe wall, and the vibration due to the sudden pressure fluctuation can be suppressed. Here, the partition plate 77 and the rectifying plate 75 may be interchanged with each other, and the rectifying plate 76 used in the modification of the first embodiment may be used instead of the mesh-shaped rectifying plate 75. to be. Other configurations, operations and effects are the same as in the first embodiment.

Modified example of the third embodiment

The modification of the said 3rd Embodiment is demonstrated, referring FIG. In this modification, the third embodiment uses the buffer container 71 in a vertical state instead of using the buffer container 71 in a horizontal state. That is, in the third embodiment, the refrigerant flowing into the buffer container 71 flows in the horizontal direction, but in the present modification, the refrigerant flows in the vertical direction.

Specifically, the buffer container 71 is disposed so that the body portion 72 extends in the vertical direction, and the upper end surface of the body portion 72 is blocked by the inlet end 73, and the lower end surface is the outlet side. Blocked with an end 74. That is, the buffer container 71 is formed of a cylindrical container extending in the vertical direction. Then, the outlet port 33 is connected to the upper portion of the body portion 72 that is the upper side of the buffer container 71, the connection pipe (P) in the center of the outlet side end 74, which is the lower surface of the buffer container 71 Connected.

In the buffer container 71, the refrigerant flowing from the outlet port 33 flows vertically downward. That is, not only the gas refrigerant introduced but also the liquid refrigerant flows from the top to the bottom and flows out into the connection pipe P. Therefore, it is possible to prevent the liquid refrigerant from being stored in the buffer container 71. The outlet port 35 may be connected to an inlet side end 73 which is the upper surface of the buffer container 71. Other configurations, operations and effects are the same as in the first embodiment.

Other Embodiments

For example, the shape of the rectifying plates 75 and 76 in each said embodiment is not limited to this. That is, the cross-sectional shape of the said rectifying plates 75 and 76 may be formed in the shape of a circle or polygon which has the area which occupies about the cross section of the buffer container 71 substantially.

In addition, the number of the said rectifying plates 75 is not limited to one, You may arrange | position so that two or more may adjoin in parallel.

In addition, the shape of the said buffer container 71 is not limited to a cylindrical shape. That is, the buffer container 71 may be formed in a rectangular cylindrical shape as viewed from the cross section, which extends along the flow direction of the coolant, or may be formed so that the flow passage cross-sectional area of the coolant gradually expands from the inlet side to the outlet side.

Here, the above embodiment is essentially a preferable example, and does not intend limitation of this invention, its application, or its use range.

As described above, the present invention is useful as a refrigerating device having a refrigerant circuit having a volume expander.

Claims (8)

In the refrigerating device provided with the refrigerant | coolant circuit 20 which the volume expander 60 is pipe-connected and performs a vapor compression refrigeration cycle, The refrigerant circuit 20 has a larger flow passage cross sectional area of the refrigerant than the outlet pipe during the outlet pipe of the volume expander 60, and alleviates pressure fluctuations of the refrigerant flowing out of the volume expander 60. Refrigerating apparatus, characterized in that it comprises a flow path expanding portion (71). In the refrigerating device provided with the refrigerant | coolant circuit 20 which the volume expander 60 is pipe-connected and performs a vapor compression refrigeration cycle, The coolant circuit 20 has a larger flow passage cross-sectional area of the coolant than the outlet pipe during the outlet pipe of the volume expander 60, and has a tubular flow path enlarged part 71 extending along the flow direction of the coolant. Refrigerating apparatus comprising a). The method according to claim 2, The flow passage enlargement portion 71 is disposed in a state extending in the up and down direction, and is connected to an outlet side pipe of the volume expander 60 so that the coolant flowing from the upper portion flows downward vertically and flows out from the lower surface. Refrigeration apparatus. The method according to claim 1 or 2, Refrigerating device, characterized in that the rectifying means (75, 76) of the refrigerant is disposed inside the passage expansion portion (71). The method according to claim 4, The rectifying means (76) is a refrigeration apparatus, characterized in that the rectifying plate is formed in a plate shape having a plurality of through holes, arranged in the flow direction of the refrigerant. The method according to claim 4, The rectifying means (75) is formed of a plate-shaped mesh member, characterized in that the rectifying plate disposed in the flow direction of the refrigerant facing. The method according to claim 2 or 3, The flow passage expanding portion (71) has a through hole and a partition plate (77) for partitioning the inside in the flow direction of the refrigerant is disposed. The refrigerator according to claim 1 or 2, wherein the refrigerant is carbon dioxide.

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